#include <iostream>
#include <string>

int main() {
    std::string text{"cat"};
    char mark{'!'};
    std::cout << text[0] << ' ' << text.size() << '\n';
    text += mark;
    std::string prefix{"a"};
    std::string joined{prefix + "b"};
    std::cout << text << ' ' << text.size() << '\n';
    std::cout << joined << ' ' << joined.size() << '\n';
    return 0;
}